1. Field of the Invention
This invention relates to a cassette ejecting device for a tape recorder or a like apparatus wherein a toggle force of a toggle spring is transmitted to a cassette holder and acts as a holding force to hold the cassette holder to a cassette operating position.
2. Description of the Prior Art
Generally, a tape recorder employing a tape cassette is constituted such that if a cassette is loaded on a cassette holder, the cassette holder is moved to a cassette operating position, and if an ejecting lever is pushed in, the cassette holder is returned to a cassette loading position.
In particular, an urging force of an urging means (a cassette holding spring) tending to move a cassette holder toward a cassette operating position is always transmitted to act upon the cassette holder by way of an interlocking member for the cassette holder. However, the cassette holder in a cassette loading position is held from movement and to the cassette loading position by a stationary member such as a chassis. Thus, if a cassette is loaded on the cassette holder, such holding by the stationary member is cancelled by such a cassette loading operation. As a result, the cassette holder is moved, for example, down, by an urging force of the cassette holding spring acting thereupon by way of the interlocking member to feed the cassette in a parallel relationship to the cassette operating position. Thus, the urging force of the cassette holding spring acts to move the cassette holder toward the cassette operating position and, after the cassette operating position is reached, acts as a holding force to hold the cassette holder to the cassette operating position.
Then, if an ejecting lever is pushed in, the cassette holder is moved toward and returns to the cassette loading position held by the stationary member, allowing ejection of the cassette. If the ejection operating force applied to the ejecting lever is removed after the cassette holder has been returned to the cassette loading position, the ejecting lever is automatically returned to its initial position by an urging force of a return spring therefor. Thus, the pushing in operation of the ejecting lever is done against the return spring and also against the urging force of the cassette holding spring acting upon the cassette holder.
It is to be noted that, in the cassette operating position, a tape within the cassette is clamped, for example, between a capstan and a pinch roller and thus runs at a fixed speed, and a magnetic head is contacted with the tape to effect desired recording on or reproduction from the tape. Further, also quick feeding or quick rewinding of the tape or temporary stopping of the tape may be done when required in the cassette operating position of the cassette holder.
In the cassette operating position, if the cassette is moved upwardly or downwardly, displacement or dislocation of a tape track relative to the magnetic head in the vertical direction will appear, making accurate recording and reproduction difficult. Accordingly, the cassette, that is, the cassette holder on which the cassette is loaded, must necessarily be held assuredly to the cassette loading position.
Again, the urging force of the cassette holding spring for the cassette holder acts also as a holding force to hold the cassette holder to the cassette loading position. Accordingly, if the urging force is increased, the cassette holder will be held more assuredly to the cassette loading position.
To the contrary, it is necessary that an ejecting operation be done lightly and readily under a low ejecting lever operating force. However, the urging force of the cassette holding spring for the cassette holder acts as a resisting force to the ejecting operation. Accordingly, if the urging force of the cassette holding force is increased, then a greater ejecting lever operating force is required and hence the ejecting operation cannot be done easily.
Thus, a cassette ejecting device is required wherein a sufficient cassette holder holding force can be obtained while an ejecting lever operating force is low, meeting such contradictory requirements as described above.
For example, a Japanese patent application No. 59-15676 discloses a cassette ejecting device wherein an urging force of a return spring for an ejecting lever and an urging force of a toggle spring both act as a cassette holder holding force in a cassette loading position.
According to the cassette ejecting device, an interlocking member for the cassette holder is mounted for pivotal motion on a chassis, and an ejecting lever is engaged with the interlocking member. Thus, a return spring for the ejecting lever provides a pivoting force to pivot the interlocking member to move a cassette holder toward its cassette operating position.
Further, a toggle spring is provided such that a toggle force thereof may be transmitted to the interlocking member by way of the ejecting lever. The ejecting member is mounted for sliding movement in the cassette holder. A pivotal spring receiving member is connected to the ejecting lever by way of a connecting rod, and the toggle spring extends between the spring receiving member and the ejecting member.
Here, as an operating member connected to an end of the toggle spring is moved, a toggle force is accumulated in the toggle spring, as well known in the art. Then, when the movable end of the toggle spring moves beyond a dead center line of the toggle spring, a toggle action appears. Thus, the accumulated toggle force is discharged instantaneously to move the operating member.
In such a construction as described above wherein the toggle spring extends between the ejecting member and the spring receiving member, the ejecting member acts as a toggle spring operating member when a cassette is loaded. Then, when the ejecting member is moved together with the loaded cassette beyond the dead center line of the toggle spring, a toggle action appears. Since the spring receiving member is connected to and hence not free from the ejecting lever, the toggle force acts also upon the ejecting member itself so that the ejecting member is absorbed into the cassette holder together with the cassette and instantaneously reaches a predetermined position. However, even after the ejecting member has reached the predetermined position, the accumulated toggle force still remains in the toggle spring. Accordingly, the ejecting member having reached the predetermined position is securely held to the predetermined position and the remaining toggle force in the toggle spring acts to tend to pivot the spring receiving member. The remaining toggle force tending to pivot the spring receiving member is transmitted to the ejecting lever by way of the connecting rod and acts in the same direction with the urging force of the return spring.
In the construction described above, the toggle force of the toggle spring is transmitted to the ejecting lever which itself causes the interlocking member to produce a pivoting force to move the cassette holder toward the cassette operating position, as described hereinabove. Accordingly, in addition to the urging force of the return spring, the toggle force of the toggle spring is transmitted to act upon the cassette holder by way of the interlocking member. In this manner, the cassette holder is acted upon not only by the urging force of the cassette holding spring for the cassette holder but also by the urging force of the return spring and the toggle force of the toggle spring. Accordingly, even if the cassette holding spring for the cassette holder is designed to have a low spring force, a sufficient holding force acts upon the cassette holder in the cassette operating position, allowing assured holding of the cassette holder. Thus, since the urging force of the cassette holding spring which acts as a resisting force upon ejecting operation can be reduced, the ejecting lever operating force can be reduced, allowing lighter and easier ejecting operation.
In ejecting operation, if the ejecting lever is pushed in sufficiently, the cassette holder is returned to the cassette loading position and the ejecting member is returned to its initial position with the cassette held thereon. Thus, the cassette is partly projected from the cassette ejecting device, allowing ejection thereof. Here, if the returning action of the cassette holding member does not occur, ejection of the cassette becomes difficult.
By the way, in the arrangement of Japanese patent application No. 59-15676 described above, the returning operation of the cassette holding member is caused by the urging force of the toggle spring. Here, if the toggle force is accumulated sufficiently in the toggle spring, a high toggle force will be produced, assuring the returning operation of the cassette. Thus, if the stroke of the ejecting lever is increased, then the spring receiving member will pivot a sufficient amount, deforming the toggle spring to a sufficient degree, and hence a high toggle force will be accumulated in the toggle force. However, if the ejecting stroke is increased, the operability is deteriorated instead and a higher ejection operating force becomes necessary, which makes light and easy ejecting operation difficult. Besides, this will increase an overall size of the cassette ejecting device. Accordingly, such increase of the ejecting stroke is not preferable.